A Thin Film Transistor Liquid Crystal Display (TFT-LCD) is one of main flat panel display devices. Based on a direction of an electric field for driving liquid crystal molecules, TFT-LCDs are divided into two types: i.e. a vertical electric field type of TFT-LCD and a horizontal electric field type of TFT-LCD. In the vertical electric field type of TFT-LCD, pixel electrodes are required to be formed on an array substrate, and common electrodes are required to be formed on a color filter substrate. In contrast, in the horizontal electric field type of TFT-LCD, both the pixel electrodes and the common electrodes are required to be formed on the array substrate simultaneously. Thus, in a process of manufacturing the horizontal electric field type of TFT-LCD, a further patterning process is required to be incorporated to form the common electrodes. The vertical electric field type of TFT-LCD includes a Twist Nematic (TN) type of TFT-LCD; and the horizontal electric field type of TFT-LCD includes a Fringe Field Switching (FFS) type of TFT-LCD and an In-Plane Switching (IPS) type of TFT-LCD. The horizontal electric field type of TFT-LCD, especially the FFS type of TFT-LCD has such advantages as wide viewing angle and high aperture ratio, and has been extensively used in the liquid crystal displays.
Based on functions, an area of the array substrates may be divided into an array area and a pad area. In particular, the array area is an operating area of the array substrate, and includes components such as signal lines (for example, gate lines, data lines and common electrode lines), pixel electrodes, common electrodes and Thin Film Transistors (TFTs). The electric field for driving the liquid crystal molecules is formed by such components. The pad area is also a crimping area on which the signal lines of the array substrate are connected to an external driving circuit (for example, a flexible circuit (Chip On Flex, COF)) after processes of cutting and grinding. Typically, merely the signal lines are provided in the pad area without components such as pixel electrodes and the TFTs. The pad area is provided on one edge or two intersecting ones of four edges of the array substrate. In the pad area, the driving circuit is connected to the signal lines of the array substrate by conductive connection lines. The conductive connection lines are generally made of Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO), because the pattern of the conductive connection lines may be formed simultaneously upon forming the pixel electrodes or the common electrodes with the material such as ITO or IZO by a patterning process, which simplifies the manufacturing process.
As illustrated in FIG. 1, in the pad area, a flexible circuit 1 is directly connected to the conductive connection lines 2, and the conductive connection lines 2 are connected to the signal lines 4 through via holes 3, so that the display signal is transmitted from the flexible circuit 1 to source-drain electrodes of the array substrate through the conductive connection lines 2.
As illustrated in FIG. 1, upon being bound with the array substrate, the flexible circuit is prone to being displaced horizontally or longitudinally. Furthermore, the conductive connection lines are conventionally arranged in a pattern of longitudinal and parallel lines (being substantially vertical to the signal lines) in the pad area, which may only compensate for the affection of longitudinally displacement of the flexible circuit. However, when the flexible circuit is displaced horizontally, a size of a contact area between the flexible circuit and the conductive connection lines is reduced dramatically, which affects the transmission of the display signal and results in the defect of non-uniformly displaying such as black blocks in huge size. In extreme cases, the display may not properly operate and severely deteriorate the quality of displaying, and such defects particularly happen in a metal oxide TFT array substrate.